<template>
    <el-breadcrumb class="app-breadcrumb" separator="/">
        <transition-group name="breadcrumb">
            <el-breadcrumb-item v-for="(item,index) in levelList" :key="item.path">
                <span v-if="item.redirect==='noRedirect'||index==levelList.length-1" class="no-redirect">{{ item.meta.title }}</span>
                <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
            </el-breadcrumb-item>
        </transition-group>
    </el-breadcrumb>
</template>

<script>
    import pathToRegexp from 'path-to-regexp';

    export default {
        data () {
            return {
                levelList: null
            };
        },
        watch: {
            $route () {
                this.getBreadcrumb();
            }
        },
        created () {
            this.getBreadcrumb();
        },
        methods: {
            getBreadcrumb () {
                // only show routes with meta.title
                let matched = this.$route.matched.filter(item => item.meta && item.meta.title);
                const first = matched[0];

                if (!this.isDashboard(first)) {
                    matched = [{path: '/dashboard', meta: {title: '控制台'}}].concat(matched);
                }

                this.levelList = matched.filter(item => item.meta && item.meta.title && item.meta.breadcrumb !== false);
            },
            isDashboard (route) {
                const name = route && route.name;
                if (!name) {
                    return false;
                }
                return name.trim().toLocaleLowerCase() === 'Dashboard'.toLocaleLowerCase();
            },
            pathCompile (path) {
                // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
                const {params} = this.$route;
                var toPath = pathToRegexp.compile(path);
                return toPath(params);
            },
            handleLink (item) {
                const {redirect, path} = item;
                if (redirect) {
                    this.$router.push(redirect);
                    return;
                }
                this.$router.push(this.pathCompile(path));
            }
        }
    };
</script>

<style lang="scss" scoped>
    .app-breadcrumb.el-breadcrumb {
        display: inline-block;
        font-size: 14px;
        line-height: 50px;
        margin-left: 8px;

        .no-redirect {
            color: #97a8be;
            cursor: text;
        }
    }
</style>
